Service frequency ranges are getting extended in the recent communication networks and radiuses of cells are gradually decreased for supporting (covering) high-speed communication and more traffic. Thus, many problems may be caused in view of applying the conventional centralized cellular radio network as it is even later. That is, since a position of the base station is fixed, flexibility of a radio link configuration is low. As a result, it has been difficult to efficiently provide communication services in a radio (wireless) environment where there is a rapid change in traffic distribution and call demands.
To address such problems, a relay, more particularly, a multi-hop relay has been considered in the next generation wireless communication system, called as Long Term Evolution Advanced (LTE-A) system or an Evolved Universal Terrestrial Radio Access (E-UTRA) system. The relay system can broaden cell service coverage by covering a partial shadow area generated within a cell region, increase system capacity, and reduce an initial installation charge since a relay (hereinafter, referred to as ‘relay station (RS)’) is established in an initial stage when a service request is not frequently made.
A communication channel between a base station and a terminal in a relay system may be configured (established) by a direct link between the base station and the terminal, or by a link between the base station and the terminal via a relay node (RN). Here, a communication channel established between the base station and the relay node is referred to as a backhaul link.
Communication methods using the backhaul link channel may be divided into an in-band backhauling and an out-band backhauling. The in-band backhauling is a method in which frequency resources are dynamically shared between a backhaul communication and a terminal communication, whereas the out-band backhauling is a method in which frequency resources for the backhaul communication are different from those of the terminal communication.
During a backhaul signal transmission via the backhaul link, a propagation delay generally occurs according to communication environments. Therefore, since a backhaul signal transmitted via the backhaul link is designed by considering the propagation delay, available resources of a backhaul link channel may change, other than fixed, depending on communication environments.
That is, the resources available as the backhaul signal are decreased in a communication environment causing a long propagation delay, while being relatively increased in a communication environment causing a short propagation delay.